Ratchet wrench having two modes of reciprocating manual input

ABSTRACT

A ratchet wrench comprises an output drive member (13,17) rotatable about a first axis, a drive housing (15) containing the output drive member, and a handle (14) on the drive housing for rotating the drive housing about the first axis. A rotary member (24) within the handle is rotatable about a second axis and a drive ring (21) extends around the output drive member. A coupling means (25) couples the rotary member to the drive ring so that rotation of the rotary member about the second axis causes rotation of the drive ring about the output drive member. The wrench also includes primary ratchet means (17, 42) for selectively unidirectionally coupling the output drive member to the housing, and secondary ratchet means (23, 43) for selectively unidirectionally coupling the output drive member to the rotary member through the drive ring whereby the output drive member (13, 37) can be rotated in a selected direction either by rotation of the handle 14 or by rotation of the rotary member (24).

This invention relates to a ratchet wrench of the kind used for drivingsocket spanners and other similar devices for securing and releasingfasteners, such as for example nuts and bolts, by turning them.

Conventional ratchet wrenches are well known devices which essentiallycomprise a mechanism for transposing reciprocating circular arcuatemovement of a handle into uni-directional rotation of a drive member forthe purposes described above. The handle is usually an arm that extendsradially outwardly from the axis of the drive member, most usually in aplane perpendicular to the drive member, although the arm can be crankedor jointed. The drive member normally has a projection such as a squaredrive shaft to be received in, for example, a fastener socket.

In addition to the arrangement described above, devices have beenproposed which have dual means of producing rotation of the drivemember. These may, for example, supplement conventional means ofoperation, using ratchet mechanisms, with rotary members on the handles,which when turned about the longitudinal axis of the handle also producerotation of the drive member.

Such devices are particularly useful in confined spaces whereconventional use of a wrench is difficult, especially if the torquerequired to rotate a fastener by hand is quite high, and the confinedspace means conventional use of the wrench would be very time-consuming.Conventional ratchet wrenches may also prove cumbersome when, forexample, a nut and bolt assembly is incapable of providing theresistance required to enable the wrench to `ratchet` or slip.

Many attempts have been made to develop on the basic concept of aratchet wrench. Some involve complex mechanisms which may proveexpensive to manufacture, and unreliable in operation. Others involveless complex designs, but accordingly do not offer the best advantage inoperation.

U.S. Pat. No. 4,299,145 employs two counter-rotating ring gearspositioned concentrically about an output drive member and a bevel geardrive pinion between them turned in either direction by a shaft throughthe wrench handle. Ratchet mechanisms for each ring gear ensure that thedrive member rotates uni-directionally whatever the direction ofrotation of the shaft, which is achieved by a spiral mechanism whichtransposes linear motion of a sleeve into rotary motion of the shaft.

A similar principle is disclosed in WO 92/07692, which employs verysimilar means except that rotation of the shaft is achieved by simplyrotating the drive handle.

Both of these devices are capable of use in the conventional fashion, byturning the handle to and fro, whereupon the teeth on opposite sides ofthe bevel gear pinion act equally on the two ring gears and transmittorque to the drive member via the two ratchet mechanisms working toturn the ring gears, or slip, together.

U.S. Pat. No. 4,699,028 is an example of a less complex device. Aconventional ratchet wrench is employed with a ratchet switch capable ofdecoupling the ratchet mechanism from the output drive member to permitthe alternative mode of operation. This is also achieved by coupling oneend of a rotatable shaft, extending through the wrench handle, to thedrive member by a single bevel gear arrangement, and the other end ofthe shaft is coupled to a "spin knob" projecting from the end of thearm. In this arrangement there is no ratchet mechanism operating in thecoupling between the "spin knob" and the output drive member. Therefore,if the direction of rotation of the "spin knob" is reversed thedirection of rotation of the output drive member will also be reversed.

In the arrangement described in U.S. Pat. No. 2,206,802 a shaft in thehandle of the wrench is coupled to the output drive member through twodriven bevel gears each with an associated ratchet pawl. Rotation of thehandle about the axis of the output drive member in either directionresults in the output drive member rotating in the same direction by theaction of the ratchet pawl. The shaft in the handle carries a continuousdrive bevel gear which meshes with the two driven bevel gears. The teethon the driven bevel gears are not continuous so that the shaft cannot berotated continuously in one direction to rotate the output drive member.To rotate the output drive member the shaft in the handle is oscillatedresulting in continuous rotation of the output drive member in onedirection by the action of the ratchet pawls.

U.S. Pat. No. 4,592,256 describes a ratchet wrench in which a singleratchet pawl is used to control the rotation of the output drive memberin a selected direction by rotation of the handle. The pawl is movedinto a neutral position to allow for rotation of the output drive memberby rotation of a shaft in the handle. Since the ratchet pawl isdisconnected in its neutral position the direction of rotation of theoutput drive member is dependent on the direction of rotation of theshaft.

The limitation of the devices employing counter-rotating gears is theircomplexity, and sheer number of parts, some which may prove expensiveand difficult to manufacture. Furthermore, all the torque is transmittedthrough the bevel gear pinion at all times, creating wear and durabilityproblems. On the other hand the invention of U.S. Pat. No. 4,699,028 hasto rely upon a very short spin knob to provide the alternative means ofrotation since the knob is permanently coupled to the drive member foreither mode of operation, and therefore has to be separate from theoperator's grip used for conventional ratchet operation. If it were notshort, the overall length of the handle would be excessive, but itsshortness means that it does not offer the operator a particularlystrong grip. In either case, the utility of the wrench is compromised.

U.S. Pat. No. 3,952,617 offers a further approach in which a rotatableshaft in the wrench handle is permanently connected to the drive memberby bevel gearing, and a double ratchet arrangement in the handle betweenthe rotatable shaft and a covering sleeve is controlled by a system ofsliding wedges. Again, all the torque is always transmitted through thebevel gears.

U.S. Pat. No. 4,545,267 describes a wrench in which the primary ratchetdrive is achieved by means of a pawl on the drive member cooperatingwith the splined interior of a housing at one end of the wrench handle.A rotatable sleeve on the wrench handle is provided for turning thedrive member in the secondary ratchet mode, through the usual bevel gearconnection, with the secondary ratchet being located inside the sleeve.However, three distinct decoupling devices are used, namely one at eachof the two ratchets (their respective neutral positions) together withan arrangement for uncoupling the bevel gear which is needed to avoidthe sleeve being turned when the wrench is used in its primaryoscillating mode.

The present invention has for an object to provide a ratchet wrench withfew parts that is capable of being reliable and advantageous inoperation.

According to U.S. Pat. No. 4,545,267, it is known to provide a ratchetwrench comprising an output drive member rotatable about a first axis, adrive housing containing said output drive member, a handle on saiddrive housing for turning said drive housing about said first axis, arotary member mounted on said handle and rotatable about a second axis,a drive ring extending around said output drive member inside thehousing coupling means coupling rotation of said rotary member aboutsaid second axis with rotation of said drive ring about said first axis,primary ratchet means for selectively uni-directionally coupling saidoutput drive member to said housing, and secondary ratchet means forselectively uni-directionally coupling said output drive member to saidrotary member through said drive ring, whereby said output drive membercan be rotated in a selected direction either by turning said handleabout said first axis or by rotating said rotary member about saidsecond axis.

According to the present invention, such a ratchet wrench may becharacterised in that said drive ring is rotatable about said first axiswith respect to said output drive member, and said secondary ratchetmeans is located between the drive ring and the output drive member.

The ratchet wrench of the invention can consequently couple the outputdrive member to the drive housing for operation by manually turning thehandle to and fro, in conditions of maximum torque and where spaceallows, reserving operation by the rotary member through the drive ringfor lower torques and/or lack of room to swing the handle. The rotarymember may be located on the handle and turned or spun by finger andthumb action in a confined space or simply for rapid rotation of thedrive member in low torque conditions. In preferred embodiments of theinvention, as will be described, the secondary ratchet action inconjunction with the rotary member is effective even in conditions oflow turn resistance in both directions, because the primary ratchetmeans can be arranged to lock the drive member against reverse rotationand so provide the necessary turn resistance to enable the secondaryratchet to slip.

The wrench may also comprise selector means adapted to switch either orboth of the primary and secondary ratchet means to engage the drivemember and turn it either clockwise or counterclockwise upon working thehandle or the rotary member as the case may be. Selector means for bothratchet means may be linked whereby both ratchet means are switchedtogether.

According to preferred aspects of the present invention the ratchetwrench has a drive housing from which a fixed arm extends as the handle.The drive member in the drive housing has an output drive axis which isperpendicular to the longitudinal axis of the wrench arm. The drive ringcomprises a bevel ring gear positioned concentrically with the drivehousing on the output drive axis. The rotary member comprises a sleeveover the arm coupled to a rotatable shaft extending coaxially throughthe arm, the inner end of which shaft is coupled to the ring gear byanother bevel gear. The sleeve may be replaced by an alternative such asa knurled wheel or knob. The rotary member may also be power driven bymotor means.

The primary ratchet means is normally located between the drive housingand the output drive member. The drive housing may have an internallysplined cylindrical surface similar to that to be found in conventionalratchet wrenches, and a ratchet pawl may be mounted in the drive member.

The secondary ratchet means may be correspondingly located between thedrive ring and the drive member. The drive ring may comprise an apertureshaped identically to that of the first drive means, and an outersurface, part of which is shaped as a bevel tooth gear, and part as aplain cylindrical surface.

In conventional operation the wrench arm is swung in the planeperpendicular to the output drive axis in the normal fashion. In a firstdirection the drive housing is coupled to the output drive member by theprimary ratchet means engaging with the drive housing, and in theopposite direction the drive housing is decoupled from the output drivemember as the ratchet mechanism `ratchets` on the splined inner surfaceof the drive housing.

During this mode of operation the drive ring rotates with the outputdrive member in the driving direction, such that the sleeve on the drivehandle remains stationary; whilst in the reverse direction, a forceproportional to the resistance of the secondary ratchet mechanism willbe imparted to the drive shaft and sleeve on the handle which can easilybe resisted to prevent the drive member from rotating.

Alternative operation is achieved by turning the sleeve, and accordinglythe inner shaft to the handle, on the longitudinal axis of the wrencharm. In the driving direction the shaft is coupled to the output drivemember by the drive ring, with the secondary ratchet means engaged, andin the opposite direction the sleeve is decoupled from the output drivemember as the latter `ratchets` over the splines of the drive ring.

During this mode of operation the drive housing `ratchets` with theoutput drive member in the driving direction of rotation of the rotarymember; and in the reverse direction, the primary ratchet means engagesthe drive member with the drive housing whilst the ring gear `ratchets`.This feature is advantageous when a loose fastener is involved.

Additionally, the arrangement of the present embodiment is such that thehighest forces imparted to the wrench are transmitted through the body,or drive housing, only, in the same manner as conventional wrenches, andnot through the bevel gears. By contrast, more complex known devicesrequire such loads to be transmitted through a plurality of complexcomponents including gear teeth. Conversely, more simple devices oftenrequire a switching act to change between the different modes ofoperation, or have no `ratchetting` provision whatsoever fornon-conventional operation. Whilst this may not prove a problem when,for example, a nut and bolt assembly is loose, it may well do so whenthe resistance offered is greater, especially if that resistance isintermittent.

A specific embodiment of a ratchet wrench in accordance with theinvention will now be described by way of example with reference to theaccompanying drawings, in which:

FIG. 1 is a perspective illustration of a preferred embodiment ofratchet wrench.

FIG. 2 is a partial cross sectional side elevation of the wrench.

FIG. 3 is an exploded perspective illustration of the wrench.

FIG. 4 is a perspective view of the underside of the wrench drivehousing.

As shown in the drawings, wrench 10 comprises a handle 11 comprising aknurled sleeve 12 on a fixed arm 14 which extends in a planeperpendicular to the longitudinal axis of a drive housing 15. An upperportion 16 of the housing has a splined cylindrical inner surface 17,whilst a lower portion 18 comprises a plain concentric cylindrical innersurface 19, below a concentric frusto-conical shoulder 20.

A bevel drive ring gear 21 comprises a plain cylindrical outer surface22, and a concentric bore which has a splined cylindrical surface 23that is in this case dimensionally identical to that of the upperportion of the housing. The ring gear is located within the lowerhousing portion 18 such that it rotates freely and concentricallytherein.

The arm 14 is a cylindrical tube integral with the drive housing inwhich a rotatable shaft 24 is mounted. The inner end of the shaft isadapted to form a bevel pinion gear 25 which fits closely against atapered inner end to the tubular arm 14 located directly adjacent drivehousing 15. Furthermore the position of the taper is such that anaperture 26 is formed on conical shoulder 20 of the housing lowerportion 18, as best seen in FIG. 4, to allow the pinion bevel gear tomesh with the bevel ring gear 21. The taper is located such that it doesnot intrude into splined cylindrical inner surface 17 of the upperportion of the drive housing.

The outer end of the shaft 24 extends beyond the arm 14, and is providedwith a splined projection 27 coupled to handle sleeve 12, and retainedby a screw 29 or other suitable fastener. The shaft is retained inposition by a sprung circlip 30 which locates in an undercut 31 insidethe arm. Sleeve 12 serves as a rotary member coupled by the shaft 24 andthe bevel pinion gear 25 to the bevel drive ring gear 21.

An output drive member 13 is positioned for concentric rotation withinthe drive housing and drive ring, by upper flange 32 which locates inrecess 33 above the housing upper portion 16. An undercut 34 is providedat the opposite lower end of the drive member for alignment with arecess 35 on the lower face of ring gear 21 such that a sprung fastener36 retains both components in housing 15. A polygonal projection 37, inthis case a standard square drive stud, incorporating a spring-loadedball 38, extends from the drive member for coupling to a conventionaldrive socket or other device to be turned by the wrench.

The output drive member 13 also carries the primary and secondaryratchet means. These comprise upper and lower slots 39, 40, whichintersect with a cylindrical axial aperture 41, and two pawls 42, 43,which are retained in the slots by pin 44 such that the pawls pivot forsimultaneous, but independent engagement with the splined inner surfacesof the upper portion of the housing, in the case of the primary ratchet,and of the drive ring gear, in the case of the secondary ratchet. Thepivotal position of the pawls is determined by a selector switch 45 inthe axial aperture 41 comprising a finger grip 54 on an upper plate 52,a spindle 46, bearing pins 47, 48, and springs 49, 50.

The switch spindle 46 is positioned for rotation in aperture 41 withupper plate 52 located in a corresponding recess 53 on the drive member.The two bearing pins 47, 48 project from the spindle such that theypress on the inward facing surfaces of pawls 42, 43. The pins arealigned to urge the pawls to pivot simultaneously in the same directionby springs 49, 50, which underlie the pins in holes 55, 56, on thespindle. The switching limits of the spindle are effected by the bearingpins touching the sides of slots 39, 40, whereas the top surface of eachslot retains the entire selector mechanism in the drive member.

In operation wrench 10 may be used in a conventional or primary mode, anon-conventional or secondary mode, or a combination of these modes ashereinafter described.

In the primary mode of operation handle 11 is swung in either directionabout the output drive axis. In one direction the primary ratchetmechanism couples drive housing 15 to drive member 13 via upper pawl 42and splined inner surface 17, to cause an output rotation of the drivemember in the same direction, whilst in the secondary ratchet mechanismlower pawl 43 engages the splined inner surface 23 of the ring gear 21,but neither drives nor slips, since these elements rotate in unison withthe wrench so long as rotary sleeve 12 does not turn on the handle 11.In the opposite direction the primary ratchet mechanism decouples drivemember 13 from the housing 15 such that no rotation of the drive memberoccurs, provided of course that there is sufficient turn resistance fromthe fastener to which the drive member is connected, whilst thesecondary ratchet mechanism including lower pawl 43 decouples the drivering 21 from drive member 13.

Thus it will be understood that in the first direction no movementbetween ring gear 21 and shaft 24 takes place so handle sleeve 12remains stationary. In the reverse direction a small force proportionalto the resistance of the secondary ratchet mechanism will be imparted tothe handle, but will be overcome as the lower pawl spring 50 yields.

In the secondary mode of operation sleeve 12 is twisted in eitherdirection about the longitudinal axis of arm 14. In one direction thesecondary ratchet mechanism couples the splined inner surface 23 of thedrive ring 21 to drive member 13 via lower pawl 43 to cause an outputrotation of the drive member in the same direction, whilst upper pawl 42of the primary ratchet decouples the drive member from the splined innersurface 17 of the drive housing. In the reverse direction the secondaryratchet mechanism decouples drive member 13 from ring gear 21, whilstupper pawl 42 couples the splined surface 17 to drive member 13 suchthat the drive member is prevented from rotating in the `ratchettingdirection` by any residual forces imparted by the drive ring on theslipping pawl 43.

Thus it will be understood that in the reverse `ratchetting` direction,because drive member 13 is held stationary by drive housing 15 whilstsleeve 12 is being turned, the tendency for very loose fasteners tocause the wrench not to ratchet is overcome. Furthermore it is possibleto use the wrench in a combination of both modes whereby twisting sleeve12 at the same time as swinging arm 14 will speed up the rotation ofdrive member 13 in the positive direction.

Whilst the invention has been described in detail many alterations andmodifications may be made within the scope thereof.

What is claimed is:
 1. A ratchet wrench for transmitting two modes of reciprocating manual input motion imparted to a handle into one rotary output motion, in which the two modes of reciprocating manual input motion are a primary mode consisting of manually turning said handle to and fro about a first axis, and a secondary mode consisting of manually rotating a rotary member to and fro on said handle about a second axis intersecting said first axis, comprising:an output drive member rotatable about a first axis, a drive housing containing the output drive member, a handle on said drive housing for turning said drive housing about a first axis, a rotary member mounted on said handle exposed for manual rotation about a second axis intersecting said first axis, a drive ring extending around said output drive member inside the housing, coupling means coupling rotation of said rotary member about said second axis with rotation of said drive ring about said first axis, primary ratchet means for selectively uni-directionally coupling said output drive member to said housing, and secondary ratchet means for selectively uni-directionally coupling said output drive member to said rotary member through said drive ring, whereby said output drive member can be rotated in a selected direction either by manually turning said handle to and fro about said first axis or by manually rotating said rotary member to and fro about said second axis; wherein said drive ring is rotatable about said first axis with respect to said output drive member, and said secondary ratchet means is located between the drive ring and the output drive member.
 2. A ratchet wrench as claimed in claim 1 wherein said secondary ratchet means comprises a splined internal cylindrical surface on said drive ring and an adjustable pawl cooperating with said splined cylindrical surface.
 3. A ratchet wrench as claimed in claim 2 wherein said primary ratchet means comprises a splined internal cylindrical surface on said drive housing and an adjustable pawl cooperating with said splined cylindrical surface on said drive housing, and both the primary pawl and the secondary pawl are carried on said output drive member.
 4. A ratchet wrench as claimed in any one of claims 1 to 3 wherein said handle comprises a cylindrical tubular arm, said rotary member comprises a shaft extending down said tubular arm, said shaft extends towards said splined internal cylindrical surface on said drive ring, and said coupling means is provided at an inner end of said shaft.
 5. A ratchet wrench as claimed in any one of claims 1 to 3 wherein said drive ring comprises a bevel gear positioned concentrically within said drive housing, said handle comprises a cylindrical tubular arm, said rotary member comprises a shaft extending down said tubular arm, and said coupling means comprises a bevel pinion on said shaft inside an end thereof and, in both primary and secondary modes of operation, engaged with said bevel gear through an aperture in said end.
 6. A ratchet wrench as claimed in any one of claims 1 to 3 wherein, in both primary and secondary modes of operation, said coupling means couples said rotary member to said drive ring, and said output drive member is always rotatable in the selected direction both by manually turning said handle about said first axis and by manually rotating said rotary member about said second axis.
 7. A ratchet wrench as claimed in any one of claims 1 to 3, wherein said rotary member on said handle comprises a manually rotatable sleeve extending outside a cylindrical fixed arm portion of said handle.
 8. A ratchet wrench as claimed in claim 3 wherein said primary and secondary ratchet means comprise linked selector means for simultaneously switching both of said primary and secondary ratchet means to engage said output drive member so as to rotate said output drive member in a selected one of two directions under the action of either said handle or said rotary member.
 9. A ratchet wrench as claimed in claim 2 wherein said primary and secondary ratchet means comprise linked selector means for simultaneously switching both of said primary and secondary ratchet means to engage said output drive member so as to rotate said output drive member in a selected one of two directions under the action of either said handle or said rotary member.
 10. A ratchet wrench as claimed in claim 1 wherein said primary and secondary ratchet means comprise linked selector means for simultaneously switching both of said primary and secondary ratchet means to engage said output drive member so as to rotate said output drive member in a selected one of two directions under the action of either said handle or said rotary member.
 11. A ratchet wrench as claimed in claim 10 wherein said primary and secondary ratchet means respectively comprise a primary pawl and a secondary pawl mounted on said drive member, and the linked selector means comprise a spindle mounted in an axial aperture within the drive member and carrying means for urging the said pawls to pivot between two operative positions corresponding to respective rotary positions of the spindle.
 12. A ratchet wrench for transmitting two modes of reciprocating manual input motion imparted to a handle into one rotary output motion, in which the two modes of reciprocating manual input motion are a primary mode consisting of manually turning said handle to and fro about a first axis, and a secondary mode consisting of manually rotating a sleeve on said handle to and fro about a second axis intersecting said first axis, comprising:an output drive member rotatable about a first axis, a drive housing containing said output drive member, a handle comprising a cylindrical tubular arm fixed on said drive housing for manually turning said drive housing about said first axis, a sleeve mounted on said handle outside said fixed arm portion thereof and manually rotatable about a second axis intersecting said first axis, a drive ring extending around said output drive member inside the housing, coupling means coupling rotation of said sleeve about said second axis with rotation of said drive ring about said first axis, primary ratchet means for selectively uni-directionally coupling said output drive member to said housing, and secondary ratchet means for selectively uni-directionally coupling said output drive member to said sleeve through said drive ring, whereby said output drive member can be rotated in a selected direction either by manually turning said handle to and fro about said first axis or by manually rotating said sleeve to and fro about said second axis; wherein said drive ring comprises a bevel gear positioned concentrically within said drive housing and rotatable about said first axis with respect to said output drive member, said secondary ratchet means is located between the drive ring and the output drive member, said sleeve is mounted on a shaft extending down said tubular arm, and said coupling means comprises a bevel pinion on said shaft inside an end thereof and, in both primary and secondary modes of operation, engaged with said bevel gear through an aperture in said end. 